The prior art discloses lighting devices comprising a wavelength conversion element in the form of a phosphor. In this case, said lighting devices comprise an excitation light source, which excites the phosphor to emit light having a different wavelength than the excitation light wavelength. By means of suitable deflection of the excitation light and of the light emitted by the phosphor, these two light paths can be combined and fed to an optical integrator.
The document CN 102385233 A discloses a lighting device for a projector comprising an excitation laser, a phosphor wheel for the wavelength conversion of the excitation laser light into conversion light, and a filter wheel, for the spectral filtering of the conversion light. The filter wheel and the phosphor wheel are arranged on a common axis and thus rotate at the same speed. The excitation laser light is reflected onto the phosphor wheel with the aid of a dichroic mirror. By contrast, the conversion light radiated back from the phosphor wheel passes through the dichroic mirror and then impinges on the filter wheel. Through a transparency segment in the phosphor wheel, the excitation laser light can pass through the phosphor wheel without being changed spectrally and is fed to the dichroic mirror via a so-called wraparound loop and is combined with the conversion light path.